The Economist Intelligence Unit. (1999). Best practices: Environment. Univerties Press.
Lua i Stíl Chicago (17ú heag.)The Economist Intelligence Unit. Best Practices: Environment. India: Univerties Press, 1999.
Lua MLA (8ú heag.)The Economist Intelligence Unit. Best Practices: Environment. Univerties Press, 1999.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.